Development of Cuboidal KNbO3@α-Fe2O3 Hybrid Nanostructures for Improved Photocatalytic and Photoelectrocatalytic Applications.

Abstract

Monophasic and hybrid nanostructures of KNbO3 and α-Fe2O3 have been prepared using a hydrothermal process for photoelectrocatalytic and photocatalytic applications. Powder X-ray diffraction studies showed the formation of KNbO3, α-Fe2O3, and KNbO3/α-Fe2O3 with average grain sizes of 18.3, 11.5, and 26.1 nm and Brunauer–Emmett–Teller (BET) specific surface areas of 4, 100, and 20 m2/gm, respectively. Under simulated solar irradiation, the as-prepared heterostructure shows enhanced photoelectrocatalytic oxygen evolution reaction (OER) activity compared to pristine KNbO3 and α-Fe2O3. Significant photocatalytic activity of as-synthesized KNbO3/α-Fe2O3 heterostructure photocatalyst was obtained for removal of methylene blue organic dye under visible light, and the percentage activity was found to be 11, 49, and 89% for KNbO3, α-Fe2O3, and KNbO3/α-Fe2O3 photocatalysts, respectively. The dielectric constant was found to be 250.2, 65.2, and 251.5 for KNbO3, α-Fe2O3, and KNbO3/α-Fe2O3 heterostructure, respectively, at 50 °C and 500 kHz frequency.